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The most stable lactones are the 5-membered γ-lactones and 6-membered δ-lactones because, as in most organic cycles, 5 and 6 membered rings minimize the strain of bond angles. β-lactones appear in a number of natural products, but are only stable in artificial conditions (i.e. a test tube). αLactones can be detected as transient species in mass spectrometry experiments. The reactions of lactones are similar to those of esters.
Many naturally-occurring lactones are γ- and δ-lactones, both saturated and unsaturated. They contribute to the aroma of fruits, butter, cheese, and other foods.
Macrocyclic lactones are also important natural products. Cyclopentadecanolide is responsible for the musklike odor of angelica root oil. Of the naturally occurring bicyclic lactones, phthalides are responsible for the odors of celery and lovage oils, and coumarin for woodruff. Lactones are present in oak wood, and they contribute to the flavour profile of barrel-aged beers.
Lactone rings occur widely as building blocks in nature, such as in ascorbic acid, kavain, nepetalactone, gluconolactone, hormones (spironolactone, mevalonolactone), enzymes (lactonase), neurotransmitters (butyrolactone, avermectins), antibiotics (macrolides like erythromycin; amphotericin B), anticancer drugs (vernolepin, epothilones), phytoestrogens (resorcylic acid lactones, cardiac glycosides). | 0 | Theoretical and Fundamental Chemistry |
While the practice of immunisation can be traced back to the 12th century, in which ancient Chinese at that time employed the technique of variolation to confer immunity to smallpox infection, the modern era of vaccination has a short history of around 200 years. It began with the invention of a vaccine by Edward Jenner in 1798 to eradicate smallpox by injecting relatively weaker cowpox virus into the human body.
The middle of the 20th century marked the golden age of vaccine science. Rapid technological advancements during this period of time enabled scientists to cultivate cell culture under controlled environments in laboratories, subsequently giving rise to the production of vaccines against poliomyelitis, measles and various communicable diseases. Conjugated vaccines were also developed using immunologic markers including capsular polysaccharide and proteins. Creation of products targeting common illnesses successfully lowered infection-related mortality and reduced public healthcare burden.
Emergence of genetic engineering techniques revolutionised the creation of vaccines. By the end of the 20th century, researchers had the ability to create recombinant vaccines apart from traditional whole-cell vaccine, for instance Hepatitis B vaccine, which uses the viral antigens to initiate immune responses.
As the manufacturing methods continue to evolve, vaccines with more complex constitutions will inevitably be generated in the future to extend their therapeutic applications to both infectious and non-infectious diseases, in order to safeguard the health of more people. | 1 | Applied and Interdisciplinary Chemistry |
*[http://www.wiley.com/legacy/college/boyer/0470003790/animations/electron_transport/electron_transport.htm Animated diagrams illustrating oxidative phosphorylation] Wiley and Co Concepts in Biochemistry
*[http://www.life.uiuc.edu/crofts/bioph354/ On-line biophysics lectures] Antony Crofts, University of Illinois at Urbana–Champaign
*[https://www.youtube.com/watch?v=PjdPTY1wHdQ ATP Synthase] Graham Johnson | 1 | Applied and Interdisciplinary Chemistry |
Increasing the substrate concentration increases the rate of reaction (enzyme activity). However, enzyme saturation limits reaction rates. An enzyme is saturated when the active sites of all the molecules are occupied most of the time. At the saturation point, the reaction will not speed up, no matter how much additional substrate is added. The graph of the reaction rate will plateau. | 1 | Applied and Interdisciplinary Chemistry |
The early form of the rule derived from Harkins 1917 study of meteorites. He reasoned as others at the time, that meteorites are more representative of the cosmological abundance of the elements. Harkins observed that even atomic number (Z) elements were about 70 times more abundant than those with odd Z. The first seven elements, making up almost 99% of the material in a meteorite, were all even numbered Z. In addition, he observed that 90% of the material consisted of only 15 different isotopes, with atomic weights in multiples of four, the approximate weight of alpha particles. Three years earlier, Oddo made a similar observation for elements in the Earths crust, speculating that elements are condensation products of helium. The nuclear core of Helium is the same as an alpha particle.
This early work connection geochemistry with nuclear physics and cosmology was greatly expanded by the Norwegian group created by Victor Goldschmidt | 0 | Theoretical and Fundamental Chemistry |
EpoRs role in lineage commitment is currently unclear. EpoR expression can extend as far back as the hematopoietic stem cell compartment. It is unknown whether EpoR signaling plays a permissive (i.e. induces only survival) or an instructive (i.e. upregulates erythroid markers to lock progenitors to a predetermined differentiation path) role in early, multipotent progenitors in order to produce sufficient erythroblast numbers. Current publications in the field suggest that it is primarily permissive. The generation of BFU-e and CFU-e progenitors was shown to be normal in rodent embryos knocked out for either Epo or EpoR. An argument against such lack of requirement is that in response to Epo or hypoxic stress, the number of early erythroid stages, the BFU-e and CFU-e, increases dramatically. However, it is unclear if it is an instructive signal or, again, a permissive signal. One additional point is that signaling pathways activated by the EpoR are common to many other receptors; replacing EpoR with prolactin receptor supports erythroid survival and differentiation in vitro. Together, these data suggest that commitment to erythroid lineage likely does not happen due to EpoRs as-yet-unknown instructive function, but possibly due to its role in survival at the multipotent progenitor stages. | 1 | Applied and Interdisciplinary Chemistry |
Bluetongue virus (BTV), a member of Orbivirus genus within the Reoviridae family causes serious disease in livestock (sheep, goat, cattle). It is non-enveloped, double-stranded RNA virus. The genome is segmented. | 1 | Applied and Interdisciplinary Chemistry |
Combustion, Explosion, and Shock Waves (Russian: Fizika Goreniya i Vzryva, Физика горения и взрыва) is the English-language translated version of the Russian peer-reviewed scientific journal, Fizika Goreniya i Vzryva. It covers the combustion of gases and materials, detonation processes, dispersal and transformation of substances, and shock-wave propagation. The editor-in-chief is Anatoly A. Vasil'ev. | 0 | Theoretical and Fundamental Chemistry |
In nuclear medicine imaging, radiopharmaceuticals are taken internally, for example, through inhalation, intravenously, or orally. Then, external detectors (gamma cameras) capture and form images from the radiation emitted by the radiopharmaceuticals. This process is unlike a diagnostic X-ray, where external radiation is passed through the body to form an image.
There are several techniques of diagnostic nuclear medicine.
* 2D: Scintigraphy ("scint") is the use of internal radionuclides to create two-dimensional images.
* 3D: SPECT is a 3D tomographic technique that uses gamma camera data from many projections and can be reconstructed in different planes. Positron emission tomography (PET) uses coincidence detection to image functional processes.
Nuclear medicine tests differ from most other imaging modalities in that nuclear medicine scans primarily show the physiological function of the system being investigated as opposed to traditional anatomical imaging such as CT or MRI. Nuclear medicine imaging studies are generally more organ-, tissue- or disease-specific (e.g.: lungs scan, heart scan, bone scan, brain scan, tumor, infection, Parkinson etc.) than those in conventional radiology imaging, which focus on a particular section of the body (e.g.: chest X-ray, abdomen/pelvis CT scan, head CT scan, etc.). In addition, there are nuclear medicine studies that allow imaging of the whole body based on certain cellular receptors or functions. Examples are whole body PET scans or PET/CT scans, gallium scans, indium white blood cell scans, MIBG and octreotide scans.
While the ability of nuclear metabolism to image disease processes from differences in metabolism is unsurpassed, it is not unique. Certain techniques such as fMRI image tissues (particularly cerebral tissues) by blood flow and thus show metabolism. Also, contrast-enhancement techniques in both CT and MRI show regions of tissue that are handling pharmaceuticals differently, due to an inflammatory process.
Diagnostic tests in nuclear medicine exploit the way that the body handles substances differently when there is disease or pathology present. The radionuclide introduced into the body is often chemically bound to a complex that acts characteristically within the body; this is commonly known as a tracer. In the presence of disease, a tracer will often be distributed around the body and/or processed differently. For example, the ligand methylene-diphosphonate (MDP) can be preferentially taken up by bone. By chemically attaching technetium-99m to MDP, radioactivity can be transported and attached to bone via the hydroxyapatite for imaging. Any increased physiological function, such as due to a fracture in the bone, will usually mean increased concentration of the tracer. This often results in the appearance of a "hot spot", which is a focal increase in radio accumulation or a general increase in radio accumulation throughout the physiological system. Some disease processes result in the exclusion of a tracer, resulting in the appearance of a "cold spot". Many tracer complexes have been developed to image or treat many different organs, glands, and physiological processes. | 1 | Applied and Interdisciplinary Chemistry |
Lipofuscin accumulation in the eye, is a major risk factor implicated in macular degeneration, a degenerative disease, and Stargardt disease, an inherited juvenile form of macular degeneration.
In the peripheral nervous system, abnormal accumulation of lipofuscin known as lipofuscinosis is associated with a family of neurodegenerative disorders – neuronal ceroid lipofuscinoses, the most common of these is Batten disease.
Also, pathological accumulation of lipofuscin is implicated in Alzheimers disease, Parkinsons disease, amyotrophic lateral sclerosis, certain lysosomal diseases, acromegaly, denervation atrophy, lipid myopathy, chronic obstructive pulmonary disease, and centronuclear myopathy. Accumulation of lipofuscin in the colon is the cause of the condition melanosis coli.
On the other hand, myocardial lipofuscin accumulation more directly reflects chronological ageing rather than human cardiac pathology. | 1 | Applied and Interdisciplinary Chemistry |
Rutherford is known as "the father of nuclear physics" because his research, and work done under him as laboratory director, established the nuclear structure of the atom and the essential nature of radioactive decay as a nuclear process. Patrick Blackett, a research fellow working under Rutherford, using natural alpha particles, demonstrated induced nuclear transmutation. Later, Rutherfords team, using protons from an accelerator, demonstrated artificially-induced' nuclear reactions and transmutation.
Rutherford died too early to see Leó Szilárds idea of controlled nuclear chain reactions come into being. However, a speech of Rutherfords about his artificially-induced transmutation in lithium, printed in the 12 September 1933 issue of The Times, was reported by Szilárd to have been his inspiration for thinking of the possibility of a controlled energy-producing nuclear chain reaction.
Rutherfords speech touched on the 1932 work of his students John Cockcroft and Ernest Walton in "splitting" lithium into alpha particles by bombardment with protons from a particle accelerator they had constructed. Rutherford realised that the energy released from the split lithium atoms was enormous, but he also realised that the energy needed for the accelerator, and its essential inefficiency in splitting atoms in this fashion, made the project an impossibility as a practical source of energy (accelerator-induced fission of light elements remains too inefficient to be used in this way, even today). Rutherfords speech in part, read:
The element rutherfordium, Rf, Z=104, was named in honour of Rutherford in 1997. | 1 | Applied and Interdisciplinary Chemistry |
Alkaline cleaners are classified as compounds with pH 7-14. Proteins are most effectively removed from surfaces by cleaners with a pH of 11 or higher. An example of a strong alkaline cleaning agent is sodium hydroxide, also called caustic soda. Although sodium hydroxide (NaOH) can cause corrosion on food contact surfaces such as stainless steel, it is the preferred cleaning agent for protein removal due to its efficacy in dissolving proteins and dispersing/emulsifying food soils. Silicates are often added to these cleaners to reduce corrosion on metal surfaces. The mechanism of alkaline cleaning action in proteins follows a three-step process:
# Gel formation: Upon contact with the alkaline solution, the protein soil swells and forms a removable gel.
# Protein removal: The protein gel is removed through mass transfer, while the cleaning agent continues to diffuse through the soil, increasing gel formation.
# Decay stage: The protein gel has been eroded to the point where it is a thin deposit. Removal at this stage is governed by shear stress forces and mass transfer of the gel.
Hypochlorite is often added to alkaline cleaners to peptize proteins. Chlorinated cleansers work by oxidizing sulfide crosslinks in proteins. Cleaning speed and efficiency is improved due to increased diffusion of the cleaner into the soil matrix, now composed of smaller, more soluble proteins. | 1 | Applied and Interdisciplinary Chemistry |
Tiny traces of ozone in the air will attack double bonds in rubber chains, with natural rubber, polybutadiene, styrene-butadiene rubber and nitrile rubber being most sensitive to degradation. Every repeat unit in the first three materials has a double bond, so every unit can be degraded by ozone. Nitrile rubber is a copolymer of butadiene and acrylonitrile units, but the proportion of acrylonitrile is usually lower than butadiene, so attack occurs. Butyl rubber is more resistant but still has a small number of double bonds in its chains, so attack is possible. Exposed surfaces are attacked first, the density of cracks varying with ozone gas concentration. The higher the concentration, the greater the number of cracks formed.
Ozone-resistant elastomers include EPDM, fluoroelastomers like Viton and polychloroprene rubbers like Neoprene. Attack is less likely because double bonds form a very small proportion of the chains, and with the latter, the chlorination reduces the electron density in the double bonds, therefore lowering their propensity to react with ozone. Silicone rubber, Hypalon and polyurethanes are also ozone-resistant. | 0 | Theoretical and Fundamental Chemistry |
Many electrophiles are chiral and optically stable. Typically chiral electrophiles are also optically pure.
One such reagent is the fructose-derived organocatalyst used in the Shi epoxidation. The catalyst can accomplish highly enantioselective epoxidations of trans-disubstituted and trisubstituted alkenes. The Shi catalyst, a ketone, is oxidized by stoichiometric oxone to the active dioxirane form before proceeding in the catalytic cycle.
Oxaziridines such as chiral N-sulfonyloxaziridines effect enantioselective ketone alpha oxidation en route to the AB-ring segments of various natural products, including γ-rhodomycionone and α-citromycinone.
Polymer-bound chiral selenium electrophiles effect asymmetric selenenylation reactions. The reagents are aryl selenenyl bromides, and they were first developed for solution phase chemistry and then modified for solid phase bead attachment via an aryloxy moiety. The solid-phase reagents were applied toward the selenenylation of various alkenes with good enantioselectivities. The products can be cleaved from the solid support using organotin hydride reducing agents. Solid-supported reagents offers advantages over solution phase chemistry due to the ease of workup and purification. | 0 | Theoretical and Fundamental Chemistry |
The type III granules are characterized by the fact that they contain several tubules with thick walls. The ferritin present in the granules is associated with filament-like features contained in them. | 1 | Applied and Interdisciplinary Chemistry |
* Liquid chromatography: Traditional chromatography columns were made of glass. Modern columns are mostly made of borosilicate glass, acrylic glass or stainless steel. To prevent the stationary phase from leaking out of the column interior a polymer, stainless steel or ceramic net is usually applied. Depending on the application material- and size-requirements may change.
* Gas chromatography (GC): Older columns were made of glass or metal packed with particles of a solid stationary phase. More recently, narrower diameter (capillary) columns have been made using fused silica coated on the inside with a film of the stationary phase material. GC columns are typically very long to take advantage of their low resistance to the flow of carrier gas. The materials of the column and the stationary phase must be suitable for GC operating temperatures, which may range as high as 300°C or more. | 0 | Theoretical and Fundamental Chemistry |
Sensible heat is heat exchanged by a body or thermodynamic system in which the exchange of heat changes the temperature of the body or system, and some macroscopic variables of the body or system, but leaves unchanged certain other macroscopic variables of the body or system, such as volume or pressure. | 0 | Theoretical and Fundamental Chemistry |
Besides the smelters named so far, the BBOC has been licensed to the operators of the Trail smelter in British Columbia, the Belledune smelter in New Brunswick, the Noyelles Godault smelter in France, the Korea Zinc zinc smelter in Onsan, South Korea, and the lead smelter at Chanderiya in India. | 1 | Applied and Interdisciplinary Chemistry |
In antiquity, pewter was tin alloyed with lead and sometimes also copper. Older pewters with higher lead content are heavier, tarnish faster, and their oxidation has a darker, silver-gray color. Pewters containing lead are no longer used in items that will come in contact with the human body (such as cups, plates, or jewelry), due to the toxicity of lead. Modern pewters are available that are completely free of lead, although many pewters containing lead are still being produced for other purposes.
A typical European casting alloy contains 94% tin, 1% copper and 5% antimony. A European pewter sheet would contain 92% tin, 2% copper, and 6% antimony. Asian pewter, produced mostly in Malaysia, Singapore, and Thailand, contains a higher percentage of tin, usually 97.5% tin, 1% copper, and 1.5% antimony. This makes the alloy slightly softer.
The term Mexican pewter is used for any of various alloys of aluminium that are used for decorative items.
Pewter is also used to imitate platinum in costume jewelry. | 1 | Applied and Interdisciplinary Chemistry |
Creatine-alpha-ketoglutarate is a salt formed from alpha-ketoglutaric acid (AKG) and creatine.
Creatine is a mass-produced fitness supplement that is supposed to increase the user's muscle mass, strength and power. Creatine requires a delivery system for cell uptake. An example is arginine alpha-ketoglutarate. Arginine alpha-ketoglutarate itself is a chemical compound that is supposed to increase the blood flow to muscles and therefore, increase nutrient delivery to muscle cells.
Alpha-ketoglutarate (α-KG or AKG) itself is a central molecule in the Krebs cycle that controls the organism's overall citric acid cycle rate. It can improve bone tissue development in the skeletal muscles by decreasing protein catabolism and increasing protein synthesis. The supplement industry has theorized that binding creatine to alpha-ketoglutarate could show significant improvements in creatine delivery and uptake which would ultimately lead to greater improvements in muscle mass and performance. Still relatively new in the fitness industry, more research is needed to test the validity of its effects. | 1 | Applied and Interdisciplinary Chemistry |
Quinone methide itself arises by the degradation of tyrosine, leading ultimately to p-cresol. Various quinone methides are directly involved in the process of lignification (creation of complex lignin polymers) in plants.
Quinone methides have been implicated as the ultimate cytotoxins responsible for the effects of such agents as antitumor drugs, antibiotics, and DNA alkylators. Oxidation to a reactive quinone methide is the mechanistic basis of many phenolic anti-cancer drugs.
Celastrol is a triterpenoid quinone methide isolated from Tripterygium wilfordii (Thunder of God vine) and Celastrus regelii that exhibits antioxidant (15 times the potency of α-tocopherol), anti-inflammatory, anticancer, and insecticidal activities.
Pristimerin, the methyl ester of celasterol, is a triterpenoid quinone methide isolated from Maytenus heterophylla that displays antitumor and antiviral activities. Pristimerin has also been found to have a contraceptive effect due to its inhibiting effect on the calcium channel of sperm (CatSper).
Taxodone and its oxidized rearrangement product, taxodione, are diterpenoid quinone methides found in Taxodium distichum (bald cypress), Rosmarinus officinalis (rosemary), several Salvia species and other plants, that display anticancer, antibacterial, antioxidant, antifungal, insecticide, and antifeedant activities.
Maytenoquinone, an isomer of taxodione, is a biologically active quinone methide found in Maytenus dispermus.
Kendomycin is an antitumor antibacterial quinone methide macrolide first isolated from the bacterium Streptomyces violaceoruber. It has potent activity as an endothelin receptor antagonist and anti-osteoporosis agent.
Elansolid A3 is a quinone methide from the bacterium Chitinophaga sancti that displays antibiotic activity. Antibacterial quinone methides, 20-epi-isoiguesterinol, 6-oxoisoiguesterin, isoiguesterin and isoiguesterinol were found in Salacia madagascariensis. Quinone methides tingenone and netzahualcoyonol were isolated from Salacia petenensis. Nortriterpenoid quinone methide amazoquinone and (7S, 8S)-7-hydroxy-7,8-dihydro-tingenone were isolated from Maytenus amazonica. An antimicrobial quinone methide, 15 alpha-hydroxypristimerin, was isolated from a South American medicinal plant, Maytenus scutioides. | 0 | Theoretical and Fundamental Chemistry |
Quantum dots (QDs) are nano-scale semiconductor particles on the order of 2–10 nm in diameter. They possess electrical properties between those of bulk semi-conductors and individual molecules, as well as optical characteristics that make them suitable for applications where fluorescence is desirable, such as medical imaging. Most QDs synthesized for medical imaging are in the form of CdSe(ZnS) core(shell) particles. CdSe QDs have been shown to possess optical properties superior to organic dyes. The ZnS shell has a two-fold effect:
# to interact with dangling bonds that would otherwise result in particle aggregation, loss of visual resolution, and impedance of quantum confinement effects
# to further increase the fluorescence of the particles themselves. | 0 | Theoretical and Fundamental Chemistry |
Phenolic acids can be found in mushroom basidiomycetes species. For example, protocatechuic acid and pyrocatechol are found in Agaricus bisporus as well as other phenylated substances like phenylacetic and phenylpyruvic acids. Other compounds like atromentin and thelephoric acid can also be isolated from fungi in the Agaricomycetes class. Orobol, an isoflavone, can be isolated from Aspergillus niger.
; In yeasts
Aromatic alcohols (example: tyrosol) are produced by the yeast Candida albicans. They are also found in beer. These molecules are quorum sensing compounds for Saccharomyces cerevisiae.
; Metabolism
Aryl-alcohol dehydrogenase uses an aromatic alcohol and NAD to produce an aromatic aldehyde, NADH and H.
Aryl-alcohol dehydrogenase (NADP+) uses an aromatic alcohol and NADP to produce an aromatic aldehyde, NADPH and H.
Aryldialkylphosphatase (also known as organophosphorus hydrolase, phosphotriesterase, and paraoxon hydrolase) uses an aryl dialkyl phosphate and HO to produce dialkyl phosphate and an aryl alcohol. | 0 | Theoretical and Fundamental Chemistry |
In grain-boundary strengthening, the grain boundaries act as pinning points impeding further dislocation propagation. Since the lattice structure of adjacent grains differs in orientation, it requires more energy for a dislocation to change directions and move into the adjacent grain. The grain boundary is also much more disordered than inside the grain, which also prevents the dislocations from moving in a continuous slip plane. Impeding this dislocation movement will hinder the onset of plasticity and hence increase the yield strength of the material.
Under an applied stress, existing dislocations and dislocations generated by Frank–Read sources will move through a crystalline lattice until encountering a grain boundary, where the large atomic mismatch between different grains creates a repulsive stress field to oppose continued dislocation motion. As more dislocations propagate to this boundary, dislocation pile up occurs as a cluster of dislocations are unable to move past the boundary. As dislocations generate repulsive stress fields, each successive dislocation will apply a repulsive force to the dislocation incident with the grain boundary. These repulsive forces act as a driving force to reduce the energetic barrier for diffusion across the boundary, such that additional pile up causes dislocation diffusion across the grain boundary, allowing further deformation in the material. Decreasing grain size decreases the amount of possible pile up at the boundary, increasing the amount of applied stress necessary to move a dislocation across a grain boundary. The higher the applied stress needed to move the dislocation, the higher the yield strength. Thus, there is then an inverse relationship between grain size and yield strength, as demonstrated by the Hall-Petch equation. However, when there is a large direction change in the orientation of the two adjacent grains, the dislocation may not necessarily move from one grain to the other but instead create a new source of dislocation in the adjacent grain. The theory remains the same that more grain boundaries create more opposition to dislocation movement and in turn strengthens the material.
Obviously, there is a limit to this mode of strengthening, as infinitely strong materials do not exist. Grain sizes can range from about (large grains) to (small grains). Lower than this, the size of dislocations begins to approach the size of the grains. At a grain size of about , only one or two dislocations can fit inside a grain (see Figure 1 above). This scheme prohibits dislocation pile-up and instead results in grain boundary diffusion. The lattice resolves the applied stress by grain boundary sliding, resulting in a decrease in the material's yield strength.
To understand the mechanism of grain boundary strengthening one must understand the nature of dislocation-dislocation interactions. Dislocations create a stress field around them given by:
where G is the material's shear modulus, b is the Burgers vector, and r is the distance from the dislocation. If the dislocations are in the right alignment with respect to each other, the local stress fields they create will repel each other. This helps dislocation movement along grains and across grain boundaries. Hence, the more dislocations are present in a grain, the greater the stress field felt by a dislocation near a grain boundary:
Interphase boundaries can also contribute to grain boundary strengthening, particularly in composite materials and precipitation-hardened alloys. Coherent IPBs, in particular, can provide additional barriers to dislocation motion, similar to grain boundaries. In contrast, non-coherent IPBs and partially coherent IPBs can act as sources of dislocations, which can lead to localized deformation and affect the mechanical properties of the material. | 1 | Applied and Interdisciplinary Chemistry |
Because alkynes have two π bonds, alkynes can form stable complexes in which they bridge two metal centers. The alkyne donates a total of four electrons, with two electrons donated to each of the metals. And example of a complex with this bonding scheme is η-diphenylacetylene-(hexacarbonyl)dicobalt(0). | 0 | Theoretical and Fundamental Chemistry |
One improvement over the standard design of ceramic vacuum filter is to use serialized pore size distributions of non-fibrous porous ceramic filters. The porosity of this type of ceramic can be varied from 20% to 60% by volume, which allows a low-pressure drop of liquid and gas flow. Custom sizes from 1 mm diameter/0.5 mm bore of porous ceramic filters are available for a range of designs. A non-fibrous porous ceramic filter is more resistant in alkaline and acidic conditions compared to fibrous ceramic filters. Thus, it has a longer service life as it has good wearing and erosion resistance as well as being able to withstand high temperatures.
Another improvement is applied at the regeneration stage when the residual filter cake is removed by back-flushing the clean plant water to wash the internal ceramic filter. Filter cake dewatering of ceramic filters produces low final cake moistures at minimum operation and maintenance costs. The residuals moisture are removed from the filter cake due to capillary action within the ceramic elements, which rotate above the slurry level. This process gives maximum filtration, and the final cake can be maintained at the lowest moisture content due to the effective cleaning of both ceramic sectors. In addition, performance can be optimized by using an ultrasonic cleaning system to achieve efficient operation conditions for regeneration of plates. The use of filtrate in looped water cycle in the design operation can reduce the water consumption up to 30-50%. High filtrate purity can be obtained, as there is only 0.001-0.005 g/L solids in the filtrate produced from this process. This eventually results in the reduction of polymer flocculant consumption in thickeners.
Ceramic scraper knives have been introduced to this design as they are able to shave through the mass formed in filter cake dewatering. The remaining layer of solid residue on the filter provides protection from mechanical abrasion. Therefore, the maintenance costs can be reduced while the service life of the ceramic filter increases. | 0 | Theoretical and Fundamental Chemistry |
An example of photochlorination at low temperatures and under ambient pressure is the chlorination of chloromethane to dichloromethane. The liquefied chloromethane (boiling point -24 °C) is mixed with chlorine in the dark and then irradiated with a mercury-vapor lamp. The resulting dichloromethane has a boiling point of 41 °C and is later separated by distillation from methyl chloride.
The photochlorination of methane has a lower quantum yield than the chlorination of dichloromethane. Due to the high light intensity required, the intermediate products are directly chlorinated, so that mainly tetrachloromethane is formed. | 0 | Theoretical and Fundamental Chemistry |
Ocean acidification can also have effects on marine fish larvae. It internally affects their olfactory systems, which is a crucial part of their early development. Orange clownfish larvae mostly live on oceanic reefs that are surrounded by vegetative islands. Larvae are known to use their sense of smell to detect the differences between reefs surrounded by vegetative islands and reefs not surrounded by vegetative islands. Clownfish larvae need to be able to distinguish between these two destinations to be able to find a suitable area for their growth. Another use for marine fish olfactory systems is to distinguish between their parents and other adult fish, in order to avoid inbreeding.
In an experimental aquarium facility, clownfish were sustained in non-manipulated seawater with pH 8.15 ± 0.07, which is similar to our current ocean's pH. To test for effects of different pH levels, the seawater was modified to two other pH levels, which corresponded with climate change models that predict future atmospheric levels. In the year 2100 the model projects possible levels of 1,000 ppm, which correlates with the pH of 7.8 ± 0.05.
This experiment showed that when larvae are exposed to a pH of 7.8 ± 0.05 their reaction to environmental cues differs drastically from their reaction to cues at pH equal to current ocean levels. At pH 7.6 ± 0.05 larvae had no reaction to any type of cue. However, a meta-analysis published in 2022 found that the effect sizes of published studies testing for ocean acidification effects on fish behavior have declined by an order of magnitude over the past decade, and have been negligible for the past five years.
Eel embryos, a "critically endangered" species yet profound in aquaculture, are also being affected by ocean acidification, specifically the European eel. Although they spend most of their lives in fresh water, usually in rivers, streams, or estuaries, they go to spawn and die in the Sargasso Sea. Here is where European eels are experiencing the effects of acidification in one of their key life stages.
Fish embryos and larvae are usually more sensitive to pH changes than adults, as organs for pH regulation are not full developed. Because of this, European eel embryos are more vulnerable to changes in pH in the Sargasso Sea. A study of the European Eel in the Sargasso Sea was conducted in 2021 to analyze the specific effects of ocean acidification on embryos. The study found that exposure to predicted end-of-century ocean pCO conditions may affect normal development of this species in nature during sensitive early life history stages with limited physiological response capacities, while extreme acidification would negatively influence embryonic survival and development under hatchery conditions. | 0 | Theoretical and Fundamental Chemistry |
Enamines act as nucleophiles that require less acid/base activation for reactivity than their enolate counterparts. They have also been shown to offer a greater selectivity with less side reactions. There is a gradient of reactivity among different enamine types, with a greater reactivity offered by ketone enamines than their aldehyde counterparts. Cyclic ketone enamines follow a reactivity trend where the five membered ring is the most reactive due to its maximally planar conformation at the nitrogen, following the trend 5>8>6>7 (the seven membered ring being the least reactive). This trend has been attributed to the amount of p-character on the nitrogen lone pair orbital - the higher p character corresponding to a greater nucleophilicity because the p-orbital would allow for donation into the alkene π- orbital. Analogously, if the N lone pair participates in stereoelectronic interactions on the amine moiety, the lone pair will pop out of the plane (will pyramidalize) and compromise donation into the adjacent π C-C bond.
There are many ways to modulate enamine reactivity in addition to altering the steric/electronics at the nitrogen center including changing temperature, solvent, amounts of other reagents, and type of electrophile. Tuning these parameters allows for the preferential formation of E/Z enamines and also affects the formation of the more/less substituted enamine from the ketone starting material. | 0 | Theoretical and Fundamental Chemistry |
He studied chemistry at the Technical University of Munich from 1976 to 1982, receiving his diploma in 1982 with the thesis "Synthesis of anionic carbyne complexes", in the group of Professor Dr. E.O. Fischer.
In 1984 he completed his dissertation "New pathways of synthesis of anionic ketene- and carbyne complexes of 16 Group elements through neutral substituted carbyne-carbonyl complexes" also in the group of Professor Dr. E.O. Fischer at the Institute of Inorganic Chemistry, Technical University of Munich.
In 1992 he was postdoctoral lecture qualification in chemistry in the group of Professor Dr. W.A. Herrmann, Technical University of Munich, thesis: "Metal centerad coupling reactions of C1 ligands".
In 1992 he was temporary supervisor of the research group of Professor M.L.H. Green in Oxford, starting December 1992 Fellow of St. Matthews College, Oxford.
In 1993 he became professor (C3) of Inorganic Chemistry at the Humboldt-University of Berlin and in 2005 he became professor (W3) of Inorganic Chemistry at the Rheinische Friedrich-Wilhelms-Universitaet Bonn.
Filippou has made a significant contribution in the research of heavier homologues of carbon (Si, Ge, Sn, Pb) regarding the ability to form a triple bond to a metal. | 0 | Theoretical and Fundamental Chemistry |
Organic contamination comes from multiple sources throughout the semiconductor manufacturing process. Organic residues left on the device can have negative effect on the wafer quality and impact wafer yield. The organics can also be a source of food for bacteria in the ultrapure water system. Due to the quality requirements of semiconductor water, TOC must be monitored at the parts per billion level. Continuous, on-line TOC analyzers play an important role in the monitoring of water systems to help provided a reliable indication of system health. | 0 | Theoretical and Fundamental Chemistry |
Cloxacillin is an antibiotic useful for the treatment of a number of bacterial infections. This includes impetigo, cellulitis, pneumonia, septic arthritis, and otitis externa. It is not effective for methicillin-resistant Staphylococcus aureus (MRSA). It can be used by mouth and by injection.
Side effects include nausea, diarrhea, and allergic reactions including anaphylaxis. Clostridium difficile diarrhea may also occur. It is not recommended in people who have previously had a penicillin allergy. Use during pregnancy appears to be relatively safe. Cloxacillin is in the penicillin family of medications.
Cloxacillin was patented in 1960 and approved for medical use in 1965. It is on the World Health Organization's List of Essential Medicines. It is not commercially available in the United States. | 0 | Theoretical and Fundamental Chemistry |
In an Arabidopsis thaliana study, hundreds of different proteins demonstrated the possibility to bind to CaM in plants. | 1 | Applied and Interdisciplinary Chemistry |
The MGAM gene –– which is located on chromosome 7q34 –– codes for the protein Maltase-Glucoamylase. An alternative name for Maltase-Glucoamylase is glucan 1,4-alpha-glycosidase. | 1 | Applied and Interdisciplinary Chemistry |
Boroxine () is a 6-membered heterocyclic compound composed of alternating oxygen and singly-hydrogenated boron atoms. Boroxine derivatives (boronic anhydrides) such as trimethylboroxine and triphenylboroxine also make up a broader class of compounds called boroxines. These compounds are solids that are usually in equilibrium with their respective boronic acids at room temperature. Beside being used in theoretical studies, boroxine is primarily used in the production of optics. | 0 | Theoretical and Fundamental Chemistry |
The idea of microscopic reversibility was born together with physical kinetics. In 1872, Ludwig Boltzmann represented kinetics of gases as statistical ensemble of elementary collisions. Equations of mechanics are reversible in time, hence, the reverse collisions obey the same laws. This reversibility of collisions is the first example of microreversibility. According to Boltzmann, this microreversibility implies the principle of detailed balance for collisions: at the equilibrium ensemble each collision is equilibrated by its reverse collision. These ideas of Boltzmann were analyzed in detail and generalized by Richard C. Tolman.
In chemistry, J. H. van't Hoff (1884) came up with the idea that equilibrium has dynamical nature and is a result of the balance between the forward and backward reaction rates. He did not study reaction mechanisms with many elementary reactions and could not formulate the principle of detailed balance for complex reactions. In 1901, Rudolf Wegscheider introduced the principle of detailed balance for complex chemical reactions. He found that for a complex reaction the principle of detailed balance implies important and non-trivial relations between reaction rate constants for different reactions. In particular, he demonstrated that the irreversible cycles of reaction are impossible and for the reversible cycles the product of constants of the forward reactions (in the "clockwise" direction) is equal to the product of constants of the reverse reactions (in the "anticlockwise" direction). Lars Onsager (1931) used these relations in his well-known work, without direct citation but with the following remark:
The quantum theory of emission and absorption developed by Albert Einstein (1916, 1917) gives an example of application of the microreversibility and detailed balance to development of a new branch of kinetic theory.
Sometimes, the principle of detailed balance is formulated in the narrow sense, for chemical reactions only but in the history of physics it has the broader use: it was invented for collisions, used for emission and absorption of quanta, for transport processes and for many other phenomena.
In its modern form, the principle of microreversibility was published by Lewis (1925). In the classical textbooks full theory and many examples of applications are presented. | 0 | Theoretical and Fundamental Chemistry |
Most sieve analyses are carried out dry. But there are some applications which can only be carried out by wet sieving. This is the case when the sample which has to be analysed is e.g. a suspension which must not be dried; or when the sample is a very fine powder which tends to agglomerate (mostly < 45 µm) – in a dry sieving process this tendency would lead to a clogging of the sieve meshes and this would make a further sieving process impossible. A wet sieving process is set up like a dry process: the sieve stack is clamped onto the sieve shaker and the sample is placed on the top sieve. Above the top sieve a water-spray nozzle is placed which supports the sieving process additionally to the sieving motion. The rinsing is carried out until the liquid which is discharged through the receiver is clear. Sample residues on the sieves have to be dried and weighed. When it comes to wet sieving it is very important not to change the sample in its volume (no swelling, dissolving or reaction with the liquid). | 1 | Applied and Interdisciplinary Chemistry |
Microphthalmia-associated transcription factor also known as class E basic helix-loop-helix protein 32 or bHLHe32 is a protein that in humans is encoded by the MITF gene.
MITF is a basic helix-loop-helix leucine zipper transcription factor involved in lineage-specific pathway regulation of many types of cells including melanocytes, osteoclasts, and mast cells. The term "lineage-specific", since it relates to MITF, means genes or traits that are only found in a certain cell type. Therefore, MITF may be involved in the rewiring of signaling cascades that are specifically required for the survival and physiological function of their normal cell precursors.
MITF, together with transcription factor EB (TFEB), TFE3 and TFEC, belong to a subfamily of related bHLHZip proteins, termed the MiT-TFE family of transcription factors. The factors are able to form stable DNA-binding homo- and heterodimers. The gene that encodes for MITF resides at the mi locus in mice, and its protumorogenic targets include factors involved in cell death, DNA replication, repair, mitosis, microRNA production, membrane trafficking, mitochondrial metabolism, and much more. Mutation of this gene results in deafness, bone loss, small eyes, and poorly pigmented eyes and skin. In human subjects, because it is known that MITF controls the expression of various genes that are essential for normal melanin synthesis in melanocytes, mutations of MITF can lead to diseases such as melanoma, Waardenburg syndrome, and Tietz syndrome. Its function is conserved across vertebrates, including in fishes such as zebrafish and Xiphophorus.
An understanding of MITF is necessary to understand how certain lineage-specific cancers and other diseases progress. In addition, current and future research can lead to potential avenues to target this transcription factor mechanism for cancer prevention. | 1 | Applied and Interdisciplinary Chemistry |
Lampe-Önnerud is married to Per Önnerud, who she met in high school. She has two children, Anna-Maria and Mattias. | 0 | Theoretical and Fundamental Chemistry |
For cases where a very strong mechanical bond is required (such as for components that are going to be used to machine with) the components surface is often machined to create grooves for the coating to bond to. Dovetail grooves offer strong positive bonding but can be laboursome and costly. A cheaper method is to cut simple partially open grooves, yet this method produces an inferior final bond strength. The edges and corners of a component present possible weak points in the coating structure, as they can break off from the component. To increase the bond strength at these points the corners and edges of the component should be rounded off. If the coating does not need to reach the edges of a component, then an undercut can be used (as shown in the diagram to the right) to secure the coating to the substrate. Although undercuts can also be used in other scenarios.
Coatings often have a tendency to shrink after being applied due to the cooling process. This means steps need to be taken in order to minimise the negative effects of shrinking. If not, the coating can suffer from stress due to tension which will weaken the coating and in some cases may cause it to peel off. The fact coatings shrink can be used to increase the bond strength if applied wisely. Coating over the entire external surface of a component means that the coating will shrink around the component when cooled providing a sort of gripping force that will increase the mechanical bond strength. This is also the case if a flat component is sprayed over the edges, the coating will grip the surface like a clamp; again increasing bond strength. Internal coatings suffer from the effect of shrinking in that they will be pulled away from the surface of the component. To counter this the component can be heated to reduce the relative shrinking effects on cooling.
Components should be dry machined (without oils) to avoid oils being deposited on the component before spraying. If this is unavoidable then the substrate will need to be cleaned again prior to detonation spraying. | 1 | Applied and Interdisciplinary Chemistry |
TLRs are present in vertebrates as well as invertebrates. Molecular building blocks of the TLRs are represented in bacteria and in plants, and plant pattern recognition receptors are well known to be required for host defence against infection. The TLRs thus appear to be one of the most ancient, conserved components of the immune system.
In recent years TLRs were identified also in the mammalian nervous system. Members of the TLR family were detected on glia, neurons and on neural progenitor cells in which they regulate cell-fate decision.
It has been estimated that most mammalian species have between ten and fifteen types of toll-like receptors. Thirteen TLRs (named simply TLR1 to TLR13) have been identified in humans and mice together, and equivalent forms of many of these have been found in other mammalian species. However, equivalents of certain TLR found in humans are not present in all mammals. For example, a gene coding for a protein analogous to TLR10 in humans is present in mice, but appears to have been damaged at some point in the past by a retrovirus. On the other hand, mice express TLRs 11, 12, and 13, none of which is represented in humans. Other mammals may express TLRs that are not found in humans. Other non-mammalian species may have TLRs distinct from mammals, as demonstrated by the anti-cell-wall TLR14, which is found in the Takifugu pufferfish. This may complicate the process of using experimental animals as models of human innate immunity.
Vertebrate TLRs are divided by similarity into the families of TLR 1/2/6/10/14/15, TLR 3, TLR 4, TLR 5, TLR 7/8/9, and TLR 11/12/13/16/21/22/23. | 1 | Applied and Interdisciplinary Chemistry |
The reds, purples, and their blended combinations responsible for autumn foliage are derived from anthocyanins. Unlike carotenoids, anthocyanins are not present in the leaf throughout the growing season, but are produced actively, toward the end of summer. They develop in late summer in the sap of leaf cells, resulting from complex interactions of factors inside and outside the plant. Their formation depends on the breakdown of sugars in the presence of light as the level of phosphate in the leaf is reduced. Orange leaves in autumn result from a combination of anthocyanins and carotenoids.
Anthocyanins are present in approximately 10% of tree species in temperate regions, although in certain areas such as New England, up to 70% of tree species may produce anthocyanins. | 0 | Theoretical and Fundamental Chemistry |
Noboru Tokita (February 20, 1923 - October 31, 2014) was a Uniroyal and later Cabot scientist known for his work on the processing of elastomers. | 0 | Theoretical and Fundamental Chemistry |
The Chemical Society was founded in 1841, but several attempts to allow the admission of women as fellows were unsuccessful. Attempts at change included a legal challenge based on the ambiguous language of the Society’s Charter in 1880, which was defeated because the issue of admitting women as fellows "was not expedient at the present time", followed by an attempt in 1892, defeated by a Council vote of 8 to 7. However, after the election of Marie Curie as a Foreign Fellow of the Society in 1904, 19 women signed a petition for admission of women as Fellows. The petition was organised by three of its signatories: Ida Smedley, Ida Freund, and Martha Whiteley. | 1 | Applied and Interdisciplinary Chemistry |
Normal energy requirement, and therefore normal energy intake, depends mainly on age, sex and physical activity level (PAL). The Food and Agriculture Organization (FAO) of the United Nations has compiled a detailed report on human energy requirements. An older but commonly used and fairly accurate method is the Harris-Benedict equation.
Yet, there are currently ongoing studies to show if calorie restriction to below normal values have beneficial effects, and even though they are showing positive indications in nonhuman primates it is still not certain if calorie restriction has a positive effect on longevity for humans and other primates. Calorie restriction may be viewed as attaining energy balance at a lower intake and expenditure, and is, in this sense, not generally an energy imbalance, except for an initial imbalance where decreased expenditure hasn't yet matched the decreased intake. | 1 | Applied and Interdisciplinary Chemistry |
Virilization in females can manifest as clitoral enlargement, increased muscle strength, acne, hirsutism, frontal hair thinning, deepening of the voice, menstrual disruption due to anovulation, and a strengthened libido. Some of the possible causes of virilization in females are:
* Androgen-producing tumors of the
** ovaries
** adrenal glands (see adrenal tumor)
** pituitary gland (see pituitary adenoma)
* Hyperthecosis
* Hypothyroidism
* Anabolic steroid exposure
* Congenital adrenal hyperplasia due to 21-hydroxylase deficiency (late-onset)
* Conn's syndrome | 1 | Applied and Interdisciplinary Chemistry |
Continuing her interest in the f-elements, Soderholm shifted her focus from solid-state materials to nanoparticles and solutions, taking advantage of advances in X-ray structural probes made available by synchrotron facilities. Building on her earlier work using neutron scattering, her team became the first to discover that plutonium exists in solution as tiny, well-defined nanoparticles. This work solved a longstanding problem in understanding transport of plutonium in the environment and resulted in the development of a new, patented approach to separating plutonium during nuclear reprocessing. | 0 | Theoretical and Fundamental Chemistry |
The Directorate of Precious Metals & Gemstone Testing is one of fourteen directorates forming the Ministry of Industry, Commerce and Tourism. The directorate itself is composed of two sections that deal with assaying and gemmology and the three main functions of the directorate as a whole are:
1. Serving the trade and public with their gemmological and assaying needs.
2. Overseeing the local jewellery sector to ensure that traders adhere to national and international laws and nomenclature.
3. Protecting consumers and the trade from fraud within the market place.
The two sections of the Directorate deal with all aspects of gemmology and precious metal assaying and have existed for over a decade. The Assay Office was established in 1979 via Amiri Decree No.19 and the Gem & Pearl Testing Laboratory followed in 1990 via Amiri Decree No. 10.
Both sections were amongst the first to be established in the Middle East and since their establishment they have developed a positive reputation within the Middle East and beyond. | 0 | Theoretical and Fundamental Chemistry |
A powerful mixer is required for Dimetcote. To meet the high pressure requirement, the mixer should be powered by an explosion-proof electric motor or air motor. Workers can attain optimal spray characteristics by adjusting the tip size or pressure of the spray. | 1 | Applied and Interdisciplinary Chemistry |
The photochlorination of hydrocarbon is unselective, although the reactivity of the C-H bonds is tertiary>secondary>primary. At 30 °C the relative reaction rates of primary, secondary and tertiary hydrogen atoms are in a relative ratio of approximately 1 to 3.25 to 4.43. The C-C bonds remain unaffected.
Upon radiation the reaction involves alkyl and chlorine radicals following a chain reaction according to the given scheme:
Chain termination occurs by recombination of chlorine atoms. Impurities such as oxygen (present in electrochemically obtained chlorine) also cause chain termination.
The selectivity of photochlorination (with regard to substitution of primary, secondary or tertiary hydrogens) can be controlled by the interaction of the chlorine radical with the solvent, such as benzene, tert-butylbenzene or carbon disulfide. Selectivity increases in aromatic solvents. By varying the solvent the ratio of primary to secondary hydrogens can be tailored to ratios between 1: 3 to 1: 31. At higher temperatures, the reaction rates of primary, secondary and tertiary hydrogen atoms equalize. Therefore, photochlorination is usually carried out at lower temperatures. | 0 | Theoretical and Fundamental Chemistry |
Concomitant or recent (previous fourteen days) monoamine oxidase inhibitor use can lead to hypertensive reactions, including hypertensive crises.
The antihypertensive effects of methyldopa, mecamylamine, reserpine, and veratrum alkaloids may be reduced by sympathomimetics. Beta-adrenergic antagonists may also interact with sympathomimetics. Increase of ectopic pacemaker activity can occur when pseudoephedrine is used concomitantly with digitalis. Antacids increase the rate of pseudoephedrine absorption, while kaolin decreases it. | 0 | Theoretical and Fundamental Chemistry |
Poly(pentafluorophenyl acrylate) finds application in the synthesis of functional polymers by post-polymerization modification. Applications of the resulting polyacrylamides can be found in drug delivery, functional surfaces, and nanoparticles. | 0 | Theoretical and Fundamental Chemistry |
The terms "endothermic" and "endotherm" are both derived from Greek "within" and "heat", but depending on context, they can have very different meanings.
In physics, thermodynamics applies to processes involving a system and its surroundings, and the term "endothermic" is used to describe a reaction where energy is taken "(with)in" by the system (vs. an "exothermic" reaction, which releases energy "outwards").
In biology, thermoregulation is the ability of an organism to maintain its body temperature, and the term "endotherm" refers to an organism that can do so from "within" by using the heat released by its internal bodily functions (vs. an "ectotherm", which relies on external, environmental heat sources) to maintain an adequate temperature. | 0 | Theoretical and Fundamental Chemistry |
The sulfate anions reacting with different phases of the hardened cement paste (HCP) to form more voluminous reaction products can cause 3 types of expansive reactions called sulfate attack inside HCP:
# The delayed ettringite formation (DEF) also known as internal sulfate attack (ISA);
# The external sulfate attack (ESA), and;
# The thaumasite form of sulfate attack (TSA).
These three types of sulfate attack reactions are described into more details in specific sections latter in the text. When the hardened cement paste (HCP) is affected, the detrimental consequences for the structural stability of concrete structures are generally more severe than when aggregates are affected: DEF, ESA and TSA are much more damaging for concrete than ASR and ACR reactions.
A common points to all these various chemical expansive reaction is that they all require water as a reactant and as a reaction medium. The presence of water is always an aggravating factor. Concrete structures immersed in water as dams and bridge piles are therefore particularly sensitive. These reactions are also characterized by slow reaction kinetics, depending on environmental conditions such as temperature and relative humidity. They develop at a slow rate and may take several years before damages become apparent. Often a decade is needed to observe their harmful consequences. Protecting concrete structures from water contact may help to slow down the progression of the damages. | 1 | Applied and Interdisciplinary Chemistry |
With the viscosity of a sol adjusted into a proper range, both optical and refractory ceramic fibers can be drawn which are used for fiber optic sensors and thermal insulation, respectively. Thus, many ceramic materials, both glassy and crystalline, have found use in various forms from bulk solid-state components to high surface area forms such as thin films, coatings and fibers. Also, thin films have found their application in the electronic field and can be used as sensitive components of a resistive gas sensors. | 0 | Theoretical and Fundamental Chemistry |
The most common method utilized for bottom-up fabrication is self-assembled monolayers (SAM). This method usually use biological materials to form a molecular monolayer on the substrate. Nano-channels can also be fabricated from the growth of carbon nanotubes (CNT) and quantum wires. The bottom-up methods usually give well-defined shapes with characteristic length about few nanometers. For these structures to be utilized as nanofluidic devices, the interconnection between nano-channels and microfluidic systems becomes an important issue.
There exist several ways to coat the inner surface with specific charges. Diffusion-limited patterning can be utilized because a bulk solution only penetrate the entrance of a nanochannel within a certain distance. Because the diffusion speed is different for each reactant. By introducing several steps of reactants flowing into the nanochannel, it is possible to pattern the surface with different surface charges inside the channel. | 0 | Theoretical and Fundamental Chemistry |
Stanley Robert Hart (born 20 June 1935 in Swampscott, Massachusetts) is an American geologist, geochemist, leading international expert on mantle isotope geochemistry, and pioneer of chemical geodynamics. | 0 | Theoretical and Fundamental Chemistry |
Some phosphorus oxoacids have two or more P atoms in different oxidation states. One example is
* Isohypophosphoric acid, (or H(OH)(O)P−O−P(O)(OH)), a tetraprotic acid and isomer of hypophosphoric acid, containing P in oxidation state +3 and +5 | 0 | Theoretical and Fundamental Chemistry |
In addition to the conventional neutron generator design described above several other approaches exist to use electrical systems for producing neutrons. | 0 | Theoretical and Fundamental Chemistry |
Multiomics currently holds a promise to fill gaps in the understanding of human health and disease, and many researchers are working on ways to generate and analyze disease-related data. The applications range from understanding host-pathogen interactions and infectious diseases, cancer, to understanding better chronic and complex non-communicable diseases and improving personalized medicine. | 1 | Applied and Interdisciplinary Chemistry |
James Murray (1923–1961) was an organic chemist at the University of Otago. He was the first twentieth-century lichenologist in New Zealand. | 0 | Theoretical and Fundamental Chemistry |
In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformation of at least one nuclide to another. If a nucleus interacts with another nucleus or particle and they then separate without changing the nature of any nuclide, the process is simply referred to as a type of nuclear scattering, rather than a nuclear reaction.
In principle, a reaction can involve more than two particles colliding, but because the probability of three or more nuclei to meet at the same time at the same place is much less than for two nuclei, such an event is exceptionally rare (see triple alpha process for an example very close to a three-body nuclear reaction). The term "nuclear reaction" may refer either to a change in a nuclide induced by collision with another particle or to a spontaneous change of a nuclide without collision.
Natural nuclear reactions occur in the interaction between cosmic rays and matter, and nuclear reactions can be employed artificially to obtain nuclear energy, at an adjustable rate, on-demand. Nuclear chain reactions in fissionable materials produce induced nuclear fission. Various nuclear fusion reactions of light elements power the energy production of the Sun and stars. | 0 | Theoretical and Fundamental Chemistry |
Signal transducer and activator of transcription 4 (STAT4) is a transcription factor belonging to the STAT protein family, composed of STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B, STAT6. STAT proteins are key activators of gene transcription which bind to DNA in response to cytokine gradient. STAT proteins are a common part of Janus kinase (JAK)- signalling pathways, activated by cytokines.STAT4 is required for the development of Th1 cells from naive CD4+ T cells and IFN-γ production in response to IL-12. There are two known STAT4 transcripts, STAT4α and STAT4β, differing in the levels of interferon-gamma (IFN-γ )production downstream. | 1 | Applied and Interdisciplinary Chemistry |
Two mechanisms have been proposed for lithium–halogen exchange.
One proposed pathway involves a nucleophilic mechanism that generates a reversible "ate-complex" intermediate. Farnham and Calabrese crystallized an "ate-complex" lithium bis(pentafluorophenyl) iodinate complexed with TMEDA.
The "ate-complex" further reacts with electrophiles and provides pentafluorophenyl iodide and CHLi. A number of kinetic studies also support a nucleophilic pathway in which the carbanion on the lithium species attacks the halogen atom on the aryl halide. Another proposed mechanism involves single electron transfer with the generation of radicals. In reactions of secondary and tertiary alkyllithium and alkyl halides, radical species were detected by EPR spectroscopy. The mechanistic studies of lithium–halogen exchange are complicated by the formation of aggregates of organolithium species. | 0 | Theoretical and Fundamental Chemistry |
Stephen Hales, called the creator of pneumatic chemistry, created the pneumatic trough in 1727. This instrument was widely used by many chemists to explore the properties of different airs, such as what was called inflammable air (what is modernly called hydrogen). Lavoisier used this in addition to his gasometer to collect gases and analyze them, aiding him in creating his list of simple substances.
The pneumatic trough, while integral throughout the eighteenth century, was modified several times to collect gases more efficiently or just to collect more gas. For example, Cavendish noted that the amount of fixed air that was given off by a reaction was not entirely present above the water; this meant that fixed water was absorbing some of this air, and could not be used quantitatively to collect that particular air. So, he replaced the water in the trough with mercury instead, in which most airs were not soluble. By doing so, he could not only collect all airs given off by a reaction, but he could also determine the solubility of airs in water, beginning a new area of research for pneumatic chemists. While this was the major adaptation of the trough in the eighteenth century, several minor changes were made before and after this substitution of mercury for water, such as adding a shelf to rest the head on while gas collection occurred. This shelf would also allow for less conventional heads to be used, such as Brownrigg's animal bladder.
A practical application of a pneumatic trough was the eudiometer, which was used by Jan Ingenhousz to show that plants produced dephlogisticated air when exposed to sunlight, a process now called photosynthesis. | 1 | Applied and Interdisciplinary Chemistry |
The electro-absorption is a type of Stark effect in the neutral polymer, it is predominant at the electrode edge since there is a strong voltage drop. Electro-absorption can be observed from the second harmonic charge modulation spectroscopy spectra. | 0 | Theoretical and Fundamental Chemistry |
Flow of ocean water is also largely geostrophic. Just as multiple weather balloons that measure pressure as a function of height in the atmosphere are used to map the atmospheric pressure field and infer the geostrophic wind, measurements of density as a function of depth in the ocean are used to infer geostrophic currents. Satellite altimeters are also used to measure sea surface height anomaly, which permits a calculation of the geostrophic current at the surface. | 1 | Applied and Interdisciplinary Chemistry |
In engineering applications, stable stratification or convection may or may not be desirable. In either case it may be deliberately manipulated.
Stratification can strongly affect the mixing of fluids, which is important in many manufacturing processes.
* Underfloor heating deliberately creates unstable stratification of the air in a room.
* Passive cooling relies on selectively encouraging and disrupting stable stratification to cool rooms. | 1 | Applied and Interdisciplinary Chemistry |
Many isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosinolates. A prominent natural isothiocyanate is allyl isothiocyanate, also known as mustard oils.
Cruciferous vegetables, such as bok choy, broccoli, cabbage, cauliflower, kale, and others, are rich sources of glucosinolate precursors of isothiocyanates. | 0 | Theoretical and Fundamental Chemistry |
Barium chlorate is toxic to humans and can also harm the environment. It is very harmful to aquatic organisms if it is leached into bodies of water. Chemical spills of this compound, although not common, can harm entire ecosystems and should be prevented. It is necessary to dispose of this compound as hazardous waste. The Environmental Protection Agency (EPA) lists barium chlorate as hazardous. | 0 | Theoretical and Fundamental Chemistry |
Siderophores usually form a stable, hexadentate, octahedral complex preferentially with Fe compared to other naturally occurring abundant metal ions, although if there are fewer than six donor atoms water can also coordinate. The most effective siderophores are those that have three bidentate ligands per molecule, forming a hexadentate complex and causing a smaller entropic change than that caused by chelating a single ferric ion with separate ligands. Fe is a strong Lewis acid, preferring strong Lewis bases such as anionic or neutral oxygen atoms to coordinate with. Microbes usually release the iron from the siderophore by reduction to Fe which has little affinity to these ligands.
Siderophores are usually classified by the ligands used to chelate the ferric iron. The major groups of siderophores include the catecholates (phenolates), hydroxamates and carboxylates (e.g. derivatives of citric acid). Citric acid can also act as a siderophore. The wide variety of siderophores may be due to evolutionary pressures placed on microbes to produce structurally different siderophores which cannot be transported by other microbes' specific active transport systems, or in the case of pathogens deactivated by the host organism. | 1 | Applied and Interdisciplinary Chemistry |
A Surface Force Apparatus uses piezoelectric positioning elements (in addition to conventional motors for coarse adjustments), and senses the distance between the surfaces using optical interferometry. Using these sensitive elements, the device can resolve distances to within 0.1 nanometer, and forces at the 10 N level. This extremely sensitive technique can be used to measure electrostatic forces, elusive van der Waals forces, and even hydration or solvation forces. SFA is in some ways similar to using an atomic force microscope to measure interaction between a tip (or molecule adsorbed onto the tip) and a surface. The SFA, however, is more ideally suited to measuring surface-surface interactions, can measure much longer-range forces more accurately, and is well-suited to situations where long relaxation times play a role (ordering, high-viscosity, corrosion). The SFA technique is quite demanding, nevertheless, labs worldwide have adopted the technique as part of their surface science research instrumentation.
In the SFA, method two smooth cylindrically curved surfaces whose cylindrical axes are positioned at 90° to each other are made to approach each other in a direction normal to the axes. The distance between the surfaces at the point of closest approach varies between a few micrometers to a few nanometers depending on the apparatus. When the two curved cylinders have the same radius of curvature, R, this so-called crossed cylinders geometry is mathematically equivalent to the interaction between a flat surface and a sphere of radius R. Using the crossed cylinder geometry makes alignment much easier, enables testing of many different surface regions for better statistics, and also enables angle-dependent measurements to be taken. A typical setup involves R = 1 cm.
Position measurements are typically made using multiple beam interferometry (MBI). The transparent surfaces of the perpendicular cylinders, usually mica, are backed with a highly reflective material usually silver before being mounted to the glass cylinders. When a white-light source is shined normal to the perpendicular cylinders the light will reflect back and forth until it is transmitted at where the surfaces are closest. These rays create an interference pattern, known as fringes of equal chromatic order (FECO), which can be observed by microscope. Distance between the two surfaces can be determined by analyzing these patterns. Mica is used because it is extremely flat, easy to work with, and optically transparent. Any other material or molecule of interest can be coated or adsorbed onto the mica layer. | 0 | Theoretical and Fundamental Chemistry |
Fields metal, also known as Fields alloy, is a fusible alloy that becomes liquid at approximately . It is named after its inventor, Simon Quellen Field. It is a eutectic alloy of bismuth, indium, and tin, with the following mass fractions: 32.5% Bi, 51% In, 16.5% Sn.
When prepared, Fields metal can be melted in hot water. Fields metal is costly because its major component indium is expensive, priced at around double the price of silver. Because it includes neither lead nor cadmium, it is much less toxic than Wood's metal. It can be used for small-run die casting and rapid prototyping.
This alloy has been investigated as a possible liquid metal coolant in advanced nuclear power system designs. Field's metal is also of interest to nanotechnology researchers.
Although it is much less dangerous to use than other commonly melted metals, such as lead or aluminium, contact with Field's metal in the liquid state can cause third-degree burns. Indium has also been associated with Indium lung in workers frequently exposed to indium processing. | 1 | Applied and Interdisciplinary Chemistry |
Adsorption Method for Sampling of Dioxins and Furans (AMESA) is an automatic system for continuous monitoring of emissions of dioxins and furans from industrial processes which require official approval in compliance with environmental regulations. Applications include refuse incinerators and hazardous material incinerators. | 0 | Theoretical and Fundamental Chemistry |
The scaling relationship between the Richardson number and the Strouhal number is represented by the equation:
where a and b are constants depending on the condition.
For round helium buoyant jets and plumes:
When ,
When ,
For planar buoyant jets and plumes:
For shape-independent scaling: | 1 | Applied and Interdisciplinary Chemistry |
Predominant reaction in Mond Gas Process: C + 2HO = CO+ 2H
The Mond gas was composed of roughly:
* 12% CO (Carbon monoxide)
* 28% H (Hydrogen)
* 2.2% CH (Methane)
* 16% CO (Carbon dioxide)
* 42% N (Nitrogen) | 0 | Theoretical and Fundamental Chemistry |
* Encyclopædia Britannica, The New Encyclopædia Britannica, v.8 Macropaedia Ge-Hu, Encyclopædia Britannica, 1974,
* Parker, Sybil P., Dictionary of Scientific and Technical Terms. McGraw-Hill Companies, Inc., (2003) - "photosensitive glass," ,
* Maluf, Nadim et al., Introduction to Microelectromechanical Systems Engineering, Artech House, 2004,
* Paul, Amal, Chemistry of Glasses, Springer, 1990,
* Stookey, S. Donald, Journey to the Center of the Crystal Ball : An Autobiography, American Ceramic Society (1985),
* Stookey, S. Donald, Explorations in Glass: An Autobiography, Wiley-Blackwell (2000), | 0 | Theoretical and Fundamental Chemistry |
Triglycerides are synthesized by esterification of fatty acids to glycerol. Fatty acid esterification takes place in the endoplasmic reticulum of cells by metabolic pathways in which acyl groups in fatty acyl-CoAs are transferred to the hydroxyl groups of glycerol-3-phosphate and diacylglycerol. Three fatty acid chains are bonded to each glycerol molecule. Each of the three -OH groups of the glycerol reacts with the carboxyl end of a fatty acid chain (-COOH). Water is eliminated and the remaining carbon atoms are linked by an -O- bond through dehydration synthesis.
Both the adipose tissue and the liver can synthesize triglycerides. Those produced by the liver are secreted from it in the form of very-low-density lipoproteins (VLDL). VLDL particles are secreted directly into blood, where they function to deliver the endogenously derived lipids to peripheral tissues. | 1 | Applied and Interdisciplinary Chemistry |
Non-pathogenic species of the gram-positive Corynebacterium are used for the commercial production of various amino acids. The C. glutamicum species is widely used for producing glutamate and lysine, components of human food, animal feed and pharmaceutical products.
Expression of functionally active human epidermal growth factor has been done in C. glutamicum, thus demonstrating a potential for industrial-scale production of human proteins. Expressed proteins can be targeted for secretion through either the general, secretory pathway (Sec) or the twin-arginine translocation pathway (Tat).
Unlike gram-negative bacteria, the gram-positive Corynebacterium lack lipopolysaccharides that function as antigenic endotoxins in humans. | 1 | Applied and Interdisciplinary Chemistry |
Both fluence rates and irradiance of light are important signals for plants and are detected by phytochrome. Exploiting different modes of photoreversibility in this molecule allow plants to respond to different levels of light. There are three main types of fluence rate governed responses that are brought about by different levels of light. | 0 | Theoretical and Fundamental Chemistry |
In surface chemistry, the Hertz–Knudsen equation, also known as Knudsen-Langmuir equation describes evaporation rates, named after Heinrich Hertz and Martin Knudsen. | 0 | Theoretical and Fundamental Chemistry |
Fluorescein diacetate (FDA) hydrolysis assays can be used to measure the enzyme activity of microbes in a sample. A bright yellow-green glow is produced and is strongest when enzymatic activity is greatest. This can be quantified using a spectrofluorometer or a spectrophotometer. | 1 | Applied and Interdisciplinary Chemistry |
Another kind of inverse beta decay is the reaction
The Homestake experiment used the reaction
to detect solar neutrinos. | 0 | Theoretical and Fundamental Chemistry |
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid, phosphoric acid .
The phosphate or orthophosphate ion is derived from phosphoric acid by the removal of three protons . Removal of one proton gives the dihydrogen phosphate ion while removal of two protons gives the hydrogen phosphate ion . These names are also used for salts of those anions, such as ammonium dihydrogen phosphate and trisodium phosphate.
In organic chemistry, phosphate or orthophosphate is an organophosphate, an ester of orthophosphoric acid of the form where one or more hydrogen atoms are replaced by organic groups. An example is trimethyl phosphate, . The term also refers to the trivalent functional group in such esters. Phosphates may contain sulfur in place of one or more oxygen atoms (thiophosphates and organothiophosphates).
Orthophosphates are especially important among the various phosphates because of their key roles in biochemistry, biogeochemistry, and ecology, and their economic importance for agriculture and industry. The addition and removal of phosphate groups (phosphorylation and dephosphorylation) are key steps in cell metabolism.
Orthophosphates can condense to form pyrophosphates. | 0 | Theoretical and Fundamental Chemistry |
In the context of biochemistry and drug development, a hybridization assay is a type of Ligand Binding Assay (LBA) used to quantify nucleic acids in biological matrices. Hybridization assays can be in solution or on a solid support such as 96-well plates or labelled beads.
Hybridization assays involve labelled nucleic acid probes to identify related DNA or RNA molecules (i.e. with significantly high degree of sequence similarity) within a complex mixture of unlabelled nucleic acid molecules. Antisense therapy, siRNA, and other oligonucleotide and nucleic acid based biotherapeutics can be quantified with hybridization assays.
Signalling of hybridization methods can be performed using oligonucleotide probes modified in-synthesis with haptens and small molecule ligands which act homologous to the capture and detection antibodies. As with traditional ELISA, conjugates to horse radish peroxidase (HRP) or alkaline phosphatase (AP) can be used as secondary antibodies. | 1 | Applied and Interdisciplinary Chemistry |
Hot tin-dipping is the process of immersing a part into a bath of pure molten tin at a temperature greater than 450 °F or 232 °C.
Tinplate made via hot-dipped tin plating is made by cold rolling steel or iron, pickling to remove any scale, annealing to remove any strain hardening, and then coating it with a thin layer of tin. Originally this was done by producing individual or small packs of plates, which became known as the pack mill process. In the late 1920s strip mills began to replace pack mills, because they could produce the raw plates in larger quantities and more economically. | 1 | Applied and Interdisciplinary Chemistry |
Curing a thermosetting resin transforms it into a plastic, or elastomer (rubber) by crosslinking or chain extension through the formation of covalent bonds between individual chains of the polymer. Crosslink density varies depending on the monomer or prepolymer mix, and the mechanism of crosslinking:
Acrylic resins, polyesters and vinyl esters with unsaturated sites at the ends or on the backbone are generally linked by copolymerisation with unsaturated monomer diluents, with cure initiated by free radicals generated from ionizing radiation or by the photolytic or thermal decomposition of a radical initiator – the intensity of crosslinking is influenced by the degree of backbone unsaturation in the prepolymer;
Epoxy functional resins can be homo-polymerized with anionic or cationic catalysts and heat, or copolymerised through nucleophilic addition reactions with multifunctional crosslinking agents which are also known as curing agents or hardeners. As reaction proceeds, larger and larger molecules are formed and highly branched crosslinked structures develop, the rate of cure being influenced by the physical form and functionality of epoxy resins and curing agents – elevated temperature postcuring induces secondary crosslinking of backbone hydroxyl functionality which condense to form ether bonds;
Polyurethanes form when isocyanate resins and prepolymers are combined with low- or high-molecular weight polyols, with strict stoichiometric ratios being essential to control nucleophilic addition polymerisation – the degree of crosslinking and resulting physical type (elastomer or plastic) is adjusted from the molecular weight and functionality of isocyanate resins, prepolymers, and the exact combinations of diols, triols and polyols selected, with the rate of reaction being strongly influenced by catalysts and inhibitors; polyureas form virtually instantaneously when isocyanate resins are combined with long-chain amine functional polyether or polyester resins and short-chain diamine extenders – the amine-isocyanate nucleophilic addition reaction does not require catalysts. Polyureas also form when isocyanate resins come into contact with moisture;
Phenolic, amino, and furan resins all cured by polycondensation involving the release of water and heat, with cure initiation and polymerisation exotherm control influenced by curing temperature, catalyst selection or loading and processing method or pressure – the degree of pre-polymerisation and level of residual hydroxymethyl content in the resins determine the crosslink density.
Polybenzoxazines are cured by an exothermal ring-opening polymerisation without releasing any chemical, which translates in near zero shrinkage upon polymerisation.
Thermosetting polymer mixtures based on thermosetting resin monomers and pre-polymers can be formulated and applied and processed in a variety of ways to create distinctive cured properties that cannot be achieved with thermoplastic polymers or inorganic materials. | 0 | Theoretical and Fundamental Chemistry |
Grimm's Hydride Displacement Law is an early hypothesis, formulated in 1925, to describe bioisosterism, the ability of certain chemical groups to function as or mimic other chemical groups.
:“Atoms anywhere up to four places in the periodic system before an inert gas change their properties by uniting with one to four hydrogen atoms, in such a manner that the resulting combinations behave like pseudoatoms, which are similar to elements in the groups one to four places respectively, to their right.”
According to Grimm, each vertical column (of Table below) would represent a group of isosteres. | 1 | Applied and Interdisciplinary Chemistry |
Richard Wilhelm, while a missionary in China, obtained a reprinted copy in Beijing in the 1920s from members said to be an "esoteric group". According to Wilhelm, the Chinese publisher (Zhanran Huizhenzi) relied on an incomplete 17th-century version of a woodblock he had discovered in a bookstore, which he later completed with a friend's book. The Beijing bookseller only printed a few thousand copies of the work for a select audience, which included Wilhelm. Wilhelm translated the text into German in 1929, which was read by his friend Carl Gustav Jung. The English version, translated from the German by Cary Baynes, was published in 1931 with comments by Jung.
Richard Wilhelm had raised the hypothesis (now considered erroneous due to newer academic researches, as seen above) that the text expounded an orally transmitted philosophy found in early esoteric circles of China in the eighth century during the Tang dynasty. According to him, the arrival of Nestorian Christianity to China in 635 AD in the Tang dynasty and its persecution by Confucius Sects in 840 AD supported the notion that the Secret of the Golden flower could very well be encrypted Christian teachings used by the Chinese Nestorian Priests of the Luminous Religion (Chin-tan-Chiao). "Chin-Tan-Chaio" when translated can be read as the Religion of the Golden Elixir of Life which was also called the Luminous religion whose practices and philosophies were included in the Secret of the Golden Flower. According to him, the arrival of a Nestorian Christian Bishop in 635 AD and the incorporation of Eastern Christianity into China by Emperor Taizong of Tang caused the establishment of the so-called Luminous Religion in China in 635 AD. The priests of which after facing persecution in 840 AD by Emperor Wuzong of Tang, were supposedly forced to encrypt their teachings and hide them in caves. Richard Wilhelm elaborates on these speculations:Wilhelm suggested that the alleged author of the book, Lü Dongbin, who was previously referred to as Lü Yen, could have been of the Nestorian Christian Faith. | 1 | Applied and Interdisciplinary Chemistry |
FISH has been extensively studied as a diagnostic technique for the identification of pathogens in the field of medical microbiology. Although it has been proven to be a useful and applicable technique, it is still not widely applied in diagnostic laboratories. The short time to diagnosis (less than 2 hours) has been a major advantage compared with biochemical differentiation, but this advantage is challenged by MALDI-TOF-MS which allows the identification of a wider range of pathogens compared with biochemical differentiation techniques. Using FISH for diagnostic purposes has found its purpose when immediate species identification is needed, specifically for the investigation of blood cultures for which FISH is a cheap and easy technique for preliminary rapid diagnosis.
FISH can also be used to compare the genomes of two biological species, to deduce evolutionary relationships. A similar hybridization technique is called a zoo blot. Bacterial FISH probes are often primers for the 16s rRNA region.
FISH is widely used in the field of microbial ecology, to identify microorganisms. Biofilms, for example, are composed of complex (often) multi-species bacterial organizations. Preparing DNA probes for one species and performing FISH with this probe allows one to visualize the distribution of this specific species within the biofilm. Preparing probes (in two different colors) for two species allows researchers to visualize/study co-localization of these two species in the biofilm and can be useful in determining the fine architecture of the biofilm. | 1 | Applied and Interdisciplinary Chemistry |
Mitochondria (or related structures) are found in all eukaryotes (except the Oxymonad Monocercomonoides). Although commonly depicted as bean-like structures they form a highly dynamic network in the majority of cells where they constantly undergo fission and fusion. The population of all the mitochondria of a given cell constitutes the chondriome. Mitochondria vary in number and location according to cell type. A single mitochondrion is often found in unicellular organisms, while human liver cells have about 1000–2000 mitochondria per cell, making up 1/5 of the cell volume. The mitochondrial content of otherwise similar cells can vary substantially in size and membrane potential, with differences arising from sources including uneven partitioning at cell division, leading to extrinsic differences in ATP levels and downstream cellular processes. The mitochondria can be found nestled between myofibrils of muscle or wrapped around the sperm flagellum. Often, they form a complex 3D branching network inside the cell with the cytoskeleton. The association with the cytoskeleton determines mitochondrial shape, which can affect the function as well: different structures of the mitochondrial network may afford the population a variety of physical, chemical, and signalling advantages or disadvantages. Mitochondria in cells are always distributed along microtubules and the distribution of these organelles is also correlated with the endoplasmic reticulum. Recent evidence suggests that vimentin, one of the components of the cytoskeleton, is also critical to the association with the cytoskeleton. | 1 | Applied and Interdisciplinary Chemistry |
He Jiankui was planning to reveal his experiments and the birth of Lulu and Nana at the Second International Summit on Human Genome Editing, which was to be organized at the University of Hong Kong during 27–29 November 2018. However, on 25 November 2018, Antonio Regalado, senior editor for biomedicine of MIT Technology Review, posted on the journals website about the experiment based on He Jiankuis applications for conducting clinical trial that had been posted earlier on the Chinese clinical trials registry. At the time, He refused to comment on the conditions of the pregnancy. Prompted by the publicity, He immediately posted about his experiment and the successful birth of the twins on YouTube in five videos the same day. The next day, the Associated Press made the first formal news, which was most likely a pre-written account before the publicity. His experiment had received no independent confirmation, and had not been peer reviewed or published in a scientific journal. Soon after Hes revelation, the university at which He was previously employed, the Southern University of Science and Technology, stated that Hes research was conducted outside of their campus. China's National Health Commission also ordered provincial health officials to investigate his case soon after the experiment was revealed.
Amidst the furore, He was allowed to present his research at the Hong Kong meeting on 28 November under the title "CCR5 gene editing in mouse, monkey, and human embryos using CRISPR–Cas9". During the discussion session, He asserted, "Do you see your friends or relatives who may have a disease? They need help," and continued, "For millions of families with inherited disease or infectious disease, if we have this technology we can help them." In his speech, He also mentioned a second pregnancy under the same experiment. No reports disclosed, the baby might have been born around August 2019, and the birth was affirmed on 30 December when the Chinese court returned a verdict mentioning that there were "three genetically-edited babies". The baby was later revealed in 2022 as Amy. | 1 | Applied and Interdisciplinary Chemistry |
There are different enzymes to remove the glycans from the proteins or remove some part of the sugar chain.
* α2-3,6,8,9-Neuraminidase (from Arthrobacter ureafaciens): cleaves all non-reducing terminal branched and unbranched sialic acids.
* β1,4-Galactosidase (from Streptococcus pneumoniae): releases only β1,4-linked, nonreducing terminal galactose from complex carbohydrates and glycoproteins.
* β-N-Acetylglucosaminidase (from Streptococcus pneumoniae): cleaves all non-reducing terminal β-linked N-acetylglucosamine residues from complex carbohydrates and glycoproteins.
* endo-α-N-Acetylgalactosaminidase (O-glycosidase from Streptococcus pneumoniae): removes O-glycosylation. This enzyme cleaves serine- or threonine-linked unsubstituted Galβ1,3GalNAc
* PNGase F: cleaves asparagine-linked oligosaccharides unless α1,3-core fucosylated. | 0 | Theoretical and Fundamental Chemistry |
PEA is generally considered safe, and without adverse drug reactions (ADRs) or drug interactions. A 2016 study assessing safety claims in sixteen clinical trials, six case reports/pilot studies and a meta‐analysis of PEA as an analgesic, concluded that for treatment periods up to 49 days, clinical data argued against serious ADRs at an incidence of 1/200 or greater. A 2016 pooled meta-analysis involving twelve studies found that no serious ADRs were registered and/or reported. No data on interactions with PEA have been reported. Based on its mechanism, PEA may be considered likely to interact with other PPAR-α agonists used to treat high triglycerides; this remains unconfirmed. | 1 | Applied and Interdisciplinary Chemistry |
* Vorlesungen über mathematische Physik. 4 vols., B. G. Teubner, Leipzig 1876–1894.
** Vol. 1: Mechanik. 1. Auflage, B. G. Teubner, Leipzig 1876 ([http://archive.org/stream/vorlesungenberm02kircgoog#page/n7/mode/1up online]).
** Vol. 2: Mathematische Optik. B. G. Teubner, Leipzig 1891 (Herausgegeben von Kurt Hensel, [http://archive.org/stream/vorlesungenberm01plangoog#page/n14/mode/1up online]).
** Vol. 3: Electricität und Magnetismus. B. G. Teubner, Leipzig 1891 (Herausgegeben von Max Planck, [https://archive.thulb.uni-jena.de/hisbest/rsc/viewer/HisBest_derivate_00011231/KNT_63c_bild_Seite_002.tiff online]).
** Vol. 4: [https://books.google.com/books?id=t0QMSU3Q8FQC Theorie der Wärme]. B. G. Teubner, Leipzig 1894, Herausgegeben von Max Planck | 1 | Applied and Interdisciplinary Chemistry |
Although periodic droplet deformation is widely studied for its practical industrial applications, its implementation poses significant safety issues and physical limitations due to the use of electric field. In order to induce periodic droplet deformation using an electric field, an extremely large amplitude electric field must be applied. Research studies using water droplets suspended in silicone oil required root-mean-square values as high as 10^6 V/m . Even for a small electrode spacing, this type of field requires electric potentials greater than 500V, which is roughly three times wall voltage in the United States. Practically speaking, this large of an electric field can only be achieved if the electrode spacing is very small (~ O(0.1 mm)) or if a high-voltage amplifier is available. It is for this reason that the majority of studies of this phenomenon are currently being conducted in research laboratories using small diameter tubes; tubes of this size are in fact present in industrial cooling systems, such as nuclear reactors. | 1 | Applied and Interdisciplinary Chemistry |
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) is the chemical reagent with formula CCl(CN)O. This oxidant is useful for the dehydrogenation of alcohols, phenols, and steroid ketones. DDQ decomposes in water, but is stable in aqueous mineral acid. | 0 | Theoretical and Fundamental Chemistry |
There is no antidote for palytoxin. Only the symptoms can be alleviated.
Animal studies have shown that vasodilators, such as papaverine and isosorbide dinitrate, can be used as antidotes. The animal experiments only showed benefit if the antidotes were injected into the heart immediately following exposure. | 0 | Theoretical and Fundamental Chemistry |
RNA polymerase II is inhibited by α-Amanitin and other amatoxins. α-Amanitin is a highly poisonous substance found in many mushrooms. The mushroom poison has different effects on each of the RNA Polymerases: I, II, III. RNAP I is completely unresponsive to the substance and will function normally while RNAP III has a moderate sensitivity. RNAP II, however, is completely inhibited by the toxin. Alpha-Amanitin inhibits RNAP II by strong interactions in the enzyme's "funnel", "cleft", and the key "bridge α-helix" regions of the RPB-1 subunit. | 1 | Applied and Interdisciplinary Chemistry |
Polyethylene may be considered either as -[CH-CH-]- with a repeat unit of -[CH-CH]-, or as [-CH-]-, with a repeat unit of -[CH]-. Chemists tend to consider the repeat unit as -[CH-CH]- since this polymer is made from the monomer ethylene (CH=CH).
More complex repeat units can occur in vinyl polymers -[CH-CHR]-, if one hydrogen in the ethylene repeat unit is substituted by a larger fragment R. Polypropylene -[CH-CH(CH)]- has the repeat unit -[CH-CH(CH)]. Polystyrene has a chain where the substituent R is a phenyl group (CH), corresponding to a benzene ring minus one hydrogen: -[CH-CH(CH)]-, so the repeat unit is -[CH-CH(CH)]-. | 0 | Theoretical and Fundamental Chemistry |
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